Packet transfer equipment, packet transfer method resolution server, DNS server, network system and program

ABSTRACT

When a packet transfer equipment receives a packet, it extracts several types of information contained in the received packet such as the destination IP address and the destination port number and, using the extracted information as the key, inquires of a packet transfer method resolution server about the information related to the packet transfer method. The server keeps the correspondences between several types of information contained in the packet and one or more type of information related to the packet transfer method in the database and, in response to the inquiry from the packet transfer equipment, replies one or more type of information related to the packet transfer method. The packet transfer equipment rewrites several types of information such as the destination IP address and the destination port number according to one or more type of information obtained and transfers the received packet.

BACKGROUNDS OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a packet transfer equipment anda server, and particularly relates to a packet transfer equipment thattransfers the packet based on the information contained in the receivedpacket and a server to resolve the transfer method for the packet basedon the information contained in the packet.

[0003] 2. Description of the Related Art

[0004] Packet transfer equipments that transfer the received packetbased on the information contained in such packet include the followingequipments in case of those currently used in the IP (Internet Protocol)network, for example:

[0005] (i) Layer 2 switch that determines the packet transfer methodusing the information contained in the MAC header (such as destinationMAC address and VLAN-ID);

[0006] (ii) Layer 3 switch or a router that determines the packettransfer method using the information contained in the IP header (suchas the destination IP address);

[0007] (iii) Layer 4 switch that decides the packet transfer methodusing the information contained in the IP header and the TCP/UDP header(such as the port No.); and

[0008] (iv) Layer 7 switch that determines the packet transfer methodusing the information (such as URL (Universal Resource Locator) andCookie) contained in the application level header (such as the HTTP(HyperText Transport Protocol) header and the RTSP (Real Time StreamingProtocol) header).

[0009] These packet transfer equipments need the information aboutcorrespondence between the information contained in the received packetand the packet transfer method in order to determine the transfer methodfor the received packet. Conventional packet transfer equipments usethree methods as follows to obtain such information:

[0010] (a) To use the information statically set inside of the packettransfer equipment by command line interface (CLI), NMS (NetworkManagement Server) or the like;

[0011] (b) To use the information dynamically advertised to the packettransfer equipment using the information advertised from other node bythe routing protocol or the like, and

[0012] (c) To make an inquiry to an external server.

[0013] The present invention improves the method (c) among thesemethods.

[0014] Conventional examples in which a packet transfer equipmentinquires of an external server about the correspondence informationbetween the information contained in the received packet and thetransfer method for such packet include the “proxy arp” method by whichthe MAC address corresponding to a certain IP address is inquired of therouter and a method by which the web proxy server inquires of the DNS(Domain Name System) server about the IP address of the correspondingserver based on the FQDN (Fully Qualified Domain Name) of the URLcontained in the HTTP request from the user.

[0015] According to the prior arts, the packet transfer method may beasked to an external server by the proxy arp method or by the inquiry ofthe DNS server from the web proxy server as described above. However,these methods only make a one-to-one conversion in which one piece ofinformation in a particular field contained in the packet to anotherpiece of information in a particular fixed field. Specifically, theproxy arp method converts the IP address to the MAC address and the webproxy server converts the FQDN to the IP address. They just serve forresolution of the limited one-to-one correspondence.

[0016]FIG. 23 is a matrix showing combinations between the types ofinformation contained in the packet and the types of information relatedto the transfer method. In the columns classifying the types ofinformation contained in the packet, the column “1 type (Fixed)”represents that one predetermined type of information is used as the keyto find the transfer method regardless of the received packet. Thecolumn “1 type (determined for each packet)” represents that only onetype of information is used as a key, but such type is determined foreach received packet. The column “Several types (Fixed)” shows thatseveral predetermined types of information are used as the keysregardless of the received packet. The column “Several types (Determinedfor each packet)” represents that there are several types of informationused as the keys and that such several types are determined for eachreceived packet. Further, in the lines classifying the types ofinformation related to the transfer method, the line “1 type (Fixed)”represents that one predetermined type of information is used forresolution as the information related to the transfer method regardlessof the received packet and the line “1 type (Determined for eachpacket)” shows that the information for resolution is one type, but thattype is determined for each received packet. The line “Several types(Fixed)” shows that several predetermined types of information are usedfor resolution as the information related to the transfer methodregardless of the received packet and the line “Several types(determined for each packet)” shows that there are several types ofinformation for resolution and such several types are determined foreach packet.

[0017] The proxy arp method and the conventional method using a webproxy server with inquiring of an external server about the packettransfer method correspond to the combination at A in the matrix of FIG.23. Correspondence expressed by combinations at B to P other than Acannot be resolved using an external server according to the prior art.Specifically, the following correspondences cannot be resolved.

[0018] (1) Several arbitrary types of information contained in thereceived packet are used as the key to resolve one or more arbitrarytype of information related to the packet transfer method (I to P). Forexample, using both the destination port number and the destination MACaddress as the keys, the destination port number and the destination MACaddress after conversion are resolved.

[0019] (2) One type of information contained in the received packet isused as the key, but the type of the key information is determined foreach received packet (E to H). For example, the URL is rewritten usingthe URL as the key in a certain received packet and the MAC address isrewritten using the IP address as the key in another received packet.

[0020] (3) Using one fixed type of information contained in the receivedpacket as the key, several arbitrary types of information related to thetransfer method of that packet is resolved (C and D). For example, usingthe URL as the key, the URL after rewriting and the vlan tag to be addedare resolved.

[0021] (4) Using one fixed type of information contained in the receivedpacket as the key, one type of information related to the transfermethod of that packet is resolved, but the type of the resolvedinformation is decided for each received packet (B). For example, thoughthe URL is used as the key for both cases, the URL after rewriting isresolved in a certain received packet and the MAC address is resolved inanother received packet.

[0022] (5) Arbitrary combination of (1) to (4) above. For example, whenthere are two types of packets (Packet A and Packet B), the destinationport No. and the destination MAC address are rewritten before transferin case of packet A, but the URL is rewritten and the vlan tag is addedbefore transfer in case of packet B.

[0023] To resolve the correspondence as in (1) to (5) described above,there is no other method than to statically set a resolution inside ofthe packet transfer equipment using CLI or NMS instead of an externalserver according to the prior art. By this method, however, it isnecessary to set the packet transfer method for each packet transferequipment and the packet transfer equipments cannot be managedcollectively.

[0024] In addition, even if the transfer methods for correspondences (1)to (5) as described above are resolved by inquiry of an external server,it is necessary to provide a server for each type of informationprocessing method. It is necessary to have a server to resolve therewriting method of the destination port number, a server to resolve therewriting method of the destination MAC address, a server to resolve theURL rewriting method, a server to resolve the method for vlan tagaddition and so on. It is substantially impossible to actually have somany servers. It is further difficult to set a different transfer methodfor each packet.

SUMMARY OF THE INVENTION

[0025] A first object of the present invention is to provide a packettransfer equipment that can resolve the correspondences (1) to (5) asdescribed above using an external server and can transfer the receivedpacket to another node.

[0026] A second object of the present invention is to provide a serverthat can reply to inquiries about the correspondences (1) to (5) asdescribed above from the packet transfer equipment that transfers thereceived packet to another node.

[0027] According to the first aspect of the invention, a packet transferequipment that transfers the received packet to another nodecharacterized by that

[0028] the packet transfer equipment specifies several types ofinformation contained in the received packet, inquires of an externalserver about one or more type of information related to the transfermethod of the received packet and resolves the transfer method of thereceived packet according to one or more type of information obtained.

[0029] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another nodecharacterized by that

[0030] the packet transfer equipment specifies one or more type ofinformation in the received packet that is determined for each of thereceived packet, inquires of an external server about one or more typeof information related to the transfer method of the received packet andresolves the transfer method of the received packet according to one ormore type of information obtained.

[0031] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another nodecharacterized by that

[0032] the packet transfer equipment specifies one or more type ofinformation in the received packet, inquires of an external server aboutseveral types of information related to the transfer method of thereceived packet and resolves the transfer method of the received packetaccording to several types of information obtained.

[0033] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another nodecharacterized by that

[0034] the packet transfer equipment specifies one or more type ofinformation contained in the received packet, inquires of an externalserver about one or more type of information related to the transfermethod of the received packet that is determined for each of thereceived packet and resolves the transfer method of the received packetaccording to one or more type of information obtained.

[0035] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another node comprising

[0036] a packet information extraction section that extracts severaltypes of information contained in the received packet, and a packettransfer method resolution section that specifies the several types ofinformation extracted by the packet information extraction section andinquires of an external server about one or more type of informationrelated to the transfer method of the received packet and resolves thetransfer method of the received packet according to one or more type ofinformation obtained.

[0037] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another node comprising

[0038] a packet information extraction section that extracts one or moretype of information contained in the received packet that is determinedfor each of the received packet, and a packet transfer method resolutionsection that specifies the one or more type of information extracted bythe packet information extraction section, inquires of an externalserver about one or more type of information related to the transfermethod of the received packet and resolves the transfer method of thereceived packet according to one or more type of information obtained.

[0039] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another node comprising

[0040] a packet information extraction section that extracts one or moretype of information contained in the received packet, and a packettransfer method resolution section that specifies the one or more typeof information extracted by the packet information extraction section,inquires of an external server about several types of informationrelated to the transfer method of the received packet and resolves thetransfer method of the received packet according to several types ofinformation obtained.

[0041] According to another aspect of the invention, a packet transferequipment that transfers the received packet to another node comprising

[0042] a packet information extraction section that extracts one or moretype of information contained in the received packet and a packettransfer method resolution section that specifies the one or more typeof information extracted by the packet information extraction section,inquires of an external server about one or more type of informationrelated to the transfer method of the received packet that is determinedfor each of the received packet and resolves the transfer method of thereceived packet according to one or more information obtained.

[0043] According to another aspect of the invention, a packet transfermethod resolution server characterized by that,

[0044] upon a request from the packet transfer equipment that transfersthe received packet to another node inquiring the information related tothe transfer method of the received packet and specifying several typesof information contained in the received packet, one or more type ofinformation related to the transfer method of the received packet isreplied to the packet transfer equipment.

[0045] According to another aspect of the invention, a packet transfermethod resolution server characterized by that,

[0046] upon a request from the packet transfer equipment that transfersthe received packet to another node inquiring the information related tothe transfer method of the received packet and specifying one or moretype of information contained in the received packet that is determinedfor each of the received packet, one or more type of information relatedto the transfer method of the received packet is replied to the packettransfer equipment.

[0047] According to another aspect of the invention, a packet transfermethod resolution server characterized by that,

[0048] upon a request from the packet transfer equipment that transfersthe received packet to another node inquiring the information related tothe transfer method of the received packet and specifying one or moretype of information contained in the received packet, several types ofinformation related to the transfer method of the received packet arereplied to the packet transfer equipment.

[0049] According to another aspect of the invention, a packet transfermethod resolution server characterized by that,

[0050] upon a request from the packet transfer equipment that transfersthe received packet to another node inquiring the information related tothe transfer method of the received packet and specifying one or moretype of information contained in the received packet, one or more typeof information related to the transfer method of the received packetthat is determined for each of the received packet is replied to thepacket transfer equipment.

[0051] According to another aspect of the invention, a packet transfermethod resolution server comprising

[0052] a packet transfer method database where the correspondencesbetween several types of information contained in the packet and one ormore type of information related to the packet transfer method areregistered, and a packet transfer method resolution request acceptancesection that accepts the packet transfer method resolution request fromthe packet transfer equipment that transfers the received packet toanother node inquiring the information related to the transfer method ofthe received packet and specifying several types of informationcontained in the received packet, refers to the packet transfer methoddatabase and replies one or more type of information related to thetransfer method of the received packet to the packet transfer equipment.

[0053] According to another aspect of the invention, a packet transfermethod resolution server comprising

[0054] a packet transfer method database where the correspondencesbetween one or more type of information contained in the packet and oneor more type of information related to the packet transfer method areregistered, and a packet transfer method resolution request acceptancesection that accepts the packet transfer method resolution request fromthe packet transfer equipment that transfers the received packet toanother node inquiring the information related to the transfer method ofthe received packet and specifying one or more type of informationcontained in the received packet that is determined for each of thereceived packet, refers to the packet transfer method database andreplies, to the packet transfer equipment, one or more type ofinformation related to the transfer method of the received packet.

[0055] According to another aspect of the invention, a packet transfermethod resolution server comprising

[0056] a packet transfer method database where the correspondencesbetween one or more type of information contained in the packet andseveral types of information related to the packet transfer method areregistered, and a packet transfer method resolution request acceptancesection that accepts the packet transfer method resolution request fromthe packet transfer equipment that transfers the received packet toanother node inquiring the information related to the transfer method ofthe received packet and specifying one or more type of informationcontained in the received packet, refers to the packet transfer methoddatabase and replies, to the packet transfer equipment, several types ofinformation related to the transfer method of the received packet.

[0057] According to another aspect of the invention, a packet transfermethod resolution server comprising

[0058] a packet transfer method database where the correspondencesbetween one or more type of information contained in the packet and oneor more type of information related to the packet transfer method areregistered, and a packet transfer method resolution request acceptancesection that accepts the packet transfer method resolution request fromthe packet transfer equipment that transfers the received packet toanother node inquiring the information related to the transfer method ofthe received packet and specifying one or more type of informationcontained in the received packet, refers to the packet transfer methoddatabase and replies, to the packet transfer equipment, one or more typeof information related to the transfer method of the received packetthat is determined for each of the received packet.

[0059] According to another aspect of the invention, a DNS servercomprising

[0060] an IP address/FQDN correspondence database having the IP addresscorresponding to the FQDN and the FQDN corresponding to the IP addressregistered where the FQDN or the IP address in the packet transferequipment that transfers the received packet to another node uniquelyindicating several types of information contained in the received packetand the FQDN or the IP address uniquely indicating one or more type ofinformation related to the transfer method of the received packet areassociated, and a DNS resolution request acceptance section that acceptsthe IP address resolution request inquiring the IP address correspondingto the FQDN from the packet transfer equipment that transfers thereceived packet to another node, refers to the IP address/FQDNcorrespondence database and replies the IP address corresponding to theFQDN to the packet transfer equipment as well as accepts the FQDNresolution request inquiring the FQDN corresponding to the IP addressfrom the packet transfer equipment, refers to the IP address/FQDNcorrespondence database and replies the FQDN corresponding to the IPaddress to the packet transfer equipment.

[0061] According to another aspect of the invention, a DNS servercomprising

[0062] an IP address/FQDN correspondence database having the IP addresscorresponding to the FQDN and the FQDN corresponding to the IP addressregistered where the FQDN or the IP address in the packet transferequipment that transfers the received packet to another node uniquelyindicating one or more type of information in the received packetdetermined for each of the received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of the received packet are associated, and a DNSresolution request acceptance section that accepts the IP addressresolution request inquiring the IP address corresponding to the FQDNfrom the packet transfer equipment that transfers the received packet toanother node, refers to the IP address/FQDN correspondence database andreplies the IP address corresponding to the FQDN to the packet transferequipment as well as accepts the FQDN resolution request inquiring theFQDN corresponding to the IP address from the packet transfer equipment,refers to the IP address/FQDN correspondence database and replies theFQDN corresponding to the IP address to the packet transfer equipment.

[0063] According to another aspect of the invention, a DNS servercomprising

[0064] an IP address/FQDN correspondence database having the IP addresscorresponding to the FQDN and the FQDN corresponding to the IP addressregistered where the FQDN or the IP address in the packet transferequipment that transfers the received packet to another node uniquelyindicating one or more type of information in the received packet andthe FQDN or the IP address uniquely indicating several types ofinformation related to the transfer method of the received packet areassociated, and a DNS resolution request acceptance section that acceptsthe IP address resolution request inquiring the IP address correspondingto the FQDN from the packet transfer equipment that transfers thereceived packet to another node, refers to the IP address/FQDNcorrespondence database and replies the IP address corresponding to theFQDN to the packet transfer equipment as well as accepts the FQDNresolution request inquiring the FQDN corresponding to the IP addressfrom the packet transfer equipment, refers to the IP address/FQDNcorrespondence database and replies the FQDN corresponding to the IPaddress to the packet transfer equipment.

[0065] According to another aspect of the invention, a DNS servercomprising

[0066] an IP address/FQDN correspondence database having the IP addresscorresponding to the FQDN and the FQDN corresponding to the IP addressregistered where the FQDN or the IP address in the packet transferequipment that transfers the received packet to another node uniquelyindicating one or more type of information in the received packet andthe FQDN or the IP address uniquely indicating one or more type ofinformation determined for each of the received packet related to thetransfer method of the received packet are associated, and a DNSresolution request acceptance section that accepts the IP addressresolution request inquiring the IP address corresponding to the FQDNfrom the packet transfer equipment that transfers the received packet toanother node, refers to the IP address/FQDN correspondence database andreplies the IP address corresponding to the FQDN to the packet transferequipment as well as accepts the FQDN resolution request inquiring theFQDN corresponding to the IP address from the packet transfer equipment,refers to the IP address/FQDN correspondence database and replies theFQDN corresponding to the IP address to the packet transfer equipment.

[0067] According to another aspect of the invention, a network systemcomprising

[0068] a packet transfer equipment and a packet transfer methodresolution server or a DNS server, and characterized by that the policyto guide the request packet from the user requesting contents orapplication services to the server of a particular provider is describedin the packet transfer method resolution server or the DNS server.

[0069] According to another aspect of the invention, a network systemcomprising

[0070] a packet transfer equipment and a packet transfer methodresolution server or a DNS server, and characterized by that the policyto execute the transfer control of the request packet from the userrequesting the contents or application services provided by the contentsor application service provider based on the context information of theuser is described in the packet transfer method resolution server or theDNS server.

[0071] According to another aspect of the invention, a program to have acomputer function as a packet transfer equipment that transfers thereceived packet to another node comprising

[0072] a packet information extraction function to extract several typesof information contained in the received packet, and a packet transfermethod resolution function that inquires of an external server about oneor more type of information related to the transfer method of thereceived packet with specifying the several types of extractedinformation and resolves the transfer method of the received packetaccording to one or more type of information obtained.

[0073] According to another aspect of the invention, a program to have acomputer function as a packet transfer equipment that transfers thereceived packet to another node comprising

[0074] a packet information extraction function to extract one or moretype of information in the received packet determined for each of thereceived packet and a packet transfer method resolution function thatinquires of an external server about one or more type of informationrelated to the transfer method of the received packet with specifyingthe one or more type of extracted information and resolves the transfermethod of the received packet according to one or more type ofinformation obtained.

[0075] According to another aspect of the invention, a program to have acomputer function as a packet transfer equipment that transfers thereceived packet to another node comprising

[0076] a packet information extraction function to extract one or moretype of information contained in the received packet, and a packettransfer method resolution function that inquires of an external serverabout several types of information related to the transfer method of thereceived packet with specifying the one or more type of extractedinformation and resolves the transfer method of the received packetaccording to several types of information obtained.

[0077] According to another aspect of the invention, a program to have acomputer function as a packet transfer equipment that transfers thereceived packet to another node comprising

[0078] a packet information extraction function to extract one or moretype of information contained in the received packet, and a packettransfer method resolution function that inquires of an external serverabout one or more type of information related to the transfer method ofthe received packet that is determined for each of the received packetwith specifying the one or more type of extracted information andresolves the transfer method of the received packet according to one ormore type of information obtained.

[0079] According to another aspect of the invention, a program to have acomputer function as a packet transfer method resolution server providedwith a packet transfer method database where the correspondences betweenseveral types of information contained in the packet and one or moretype of information related to the packet transfer method are registeredcomprising

[0080] a packet transfer method resolution request acceptance functionthat accepts the packet transfer method resolution request from thepacket transfer equipment that transfers the received packet to anothernode inquiring the information related to the transfer method of thereceived packet and specifying several types of information contained inthe received packet, refers to the packet transfer method database andreplies to the packet transfer equipment one or more type of informationrelated to the transfer method of the received packet.

[0081] According to another aspect of the invention, a program to have acomputer function as a packet transfer method resolution server providedwith a packet transfer method database where the correspondences betweenone or more type of information contained in the packet and one or moretype of information related to the packet transfer method are registeredcomprising

[0082] a packet transfer method resolution request acceptance functionthat accepts the packet transfer method resolution request from thepacket transfer equipment that transfers the received packet to anothernode inquiring the information related to the transfer method of thereceived packet and specifying one or more type of information in thereceived packet determined for each of the received packet, refers tothe packet transfer method database and replies to the packet transferequipment one or more type of information related to the transfer methodof the received packet.

[0083] According to another aspect of the invention, a program to have acomputer function as a packet transfer method resolution server providedwith a packet transfer method database where the correspondences betweenone or more type of information contained in the packet and severaltypes of information related to the packet transfer method areregistered comprising

[0084] a packet transfer method resolution request acceptance functionthat accepts the packet transfer method resolution request from thepacket transfer equipment that transfers the received packet to anothernode inquiring the information related to the transfer method of thereceived packet and specifying one or more type of information containedin the received packet, refers to the packet transfer method databaseand replies several types of information related to the transfer methodof the received packet to the packet transfer equipment.

[0085] According to another aspect of the invention, a program to have acomputer function as a packet transfer method resolution server providedwith a packet transfer method database where the correspondences betweenone or more type of information contained in the packet and one or moretype of information related to the packet transfer method are registeredcomprising

[0086] a packet transfer method resolution request acceptance functionthat accepts the packet transfer method resolution request from thepacket transfer equipment that transfers the received packet to anothernode inquiring the information related to the transfer method of thereceived packet and specifying one or more type of information in thereceived packet, refers to the packet transfer method database andreplies to the packet transfer equipment one or more type of informationrelated to the transfer method of the received packet that is determinedfor each of the received packet.

[0087] According to another aspect of the invention, a program to have acomputer function as a DNS server provided with an IP address/FQDNcorrespondence database where the IP address corresponding to the FQDNand the FQDN corresponding to the IP address are registered and the FQDNor the IP address in the packet transfer equipment that transfers thereceived packet to another node uniquely indicating several types ofinformation contained in the received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of the received packet are associated comprising

[0088] a function that accepts the IP address resolution requestinquiring the IP address corresponding to the FQDN from the packettransfer equipment that transfers the received packet to another node,refers to the IP address/FQDN correspondence database and replies the IPaddress corresponding to the FQDN to the packet transfer equipment, anda function that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from the packet transfer equipment,refers to the IP address/FQDN correspondence database and replies theFQDN corresponding to the IP address to the packet transfer equipment.

[0089] According to another aspect of the invention, a program to have acomputer function as a DNS server provided with an IP address/FQDNcorrespondence database where the IP address corresponding to the FQDNand the FQDN corresponding to the IP address are registered and the FQDNor the IP address in the packet transfer equipment that transfers thereceived packet to another node uniquely indicating one or more type ofinformation in the received packet determined for each of the receivedpacket and the FQDN or the IP address uniquely indicating one or moretype of information related to the transfer method of the receivedpacket are associated comprising

[0090] a function that accepts the IP address resolution requestinquiring the IP address corresponding to the FQDN from the packettransfer equipment that transfers the received packet to another node,refers to the IP address/FQDN correspondence database and replies the IPaddress corresponding to the FQDN to the packet transfer equipment, anda function that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from the packet transfer equipment,refers to the IP address/FQDN correspondence database and replies theFQDN corresponding to the IP address to the packet transfer equipment.

[0091] According to another aspect of the invention, a program to have acomputer function as a DNS server provided with an IP address/FQDNcorrespondence database where the IP address corresponding to the FQDNand the FQDN corresponding to the IP address are registered and the FQDNor the IP address in the packet transfer equipment that transfers thereceived packet to another node uniquely indicating one or more type ofinformation contained in the received packet and the FQDN or the IPaddress uniquely indicating several types of information related to thetransfer method of the received packet are associated comprising

[0092] a function that accepts the IP address resolution requestinquiring the IP address corresponding to the FQDN from the packettransfer equipment that transfers the received packet to another node,refers to the IP address/FQDN correspondence database and replies the IPaddress corresponding to the FQDN to the packet transfer equipment, anda function that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from the packet transfer equipment,refers to the IP address/FQDN correspondence database and replies theFQDN corresponding to the IP address to the packet transfer equipment.

[0093] According to another aspect of the invention, a program to have acomputer function as a DNS server provided with an IP address/FQDNcorrespondence database where the IP address corresponding to the FQDNand the FQDN corresponding to the IP address are registered and the FQDNor the IP address in the packet transfer equipment that transfers thereceived packet to another node uniquely indicating one or more type ofinformation contained in the received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of the received packet that is determined for eachof the received packet are associated comprising

[0094] a function that accepts the IP address resolution requestinquiring the IP address corresponding to the FQDN from the packettransfer equipment that transfers the received packet to another node,refers to the IP address/FQDN correspondence database and replies the IPaddress corresponding to the FQDN to the packet transfer equipment, anda function that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from the packet transfer equipment,refers to the IP address/FQDN correspondence database and replies theFQDN corresponding to the IP address to the packet transfer equipment.

[0095] Thus, it becomes possible to use several types of informationcontained in the received packet as the key so as to resolve one or moretype of information related to the transfer method of that packet and toexecute the transfer.

[0096] Thus, it becomes possible to use one or more type of informationdetermined for each received packet as the key so as to resolve one ormore type of information related to the transfer method of that packetand to execute the transfer.

[0097] Thus, it becomes possible to use one type of informationcontained in the received packet as the key so as to resolve severaltypes of information related to the transfer method of that packet andto execute the transfer.

[0098] Thus, it becomes possible to use one or more type of informationcontained in the received packet as the key so as to resolve one or moretype of information related to the transfer method of that packet thatis determined for each received packet and to execute the transfer.

[0099] In the packet transfer equipment according to the presentinvention comprising of a packet transfer method storage table totemporarily store the information related to the packet transfer methodresolved by the packet transfer method resolution section, it becomesunnecessary to inquire of an external server about the informationrelated to the transfer method of the received packet every time andthus it becomes possible to effectively transfer the received packet.

[0100] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using several types of information contained in thereceived packet as the key by providing one or more type of informationrelated to the transfer method of that packet.

[0101] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using one or more type of information determined foreach received packet as the key by providing one or more type ofinformation related to the transfer method of that packet.

[0102] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using one or more type of information contained inthe received packet as the key by providing several types of informationrelated to the transfer method of that packet.

[0103] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using one or more type of information contained inthe received packet as the key by providing one or more type ofinformation related to the transfer method of that packet that isdetermined for each received packet.

[0104] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using the FQDN or the IP address uniquely indicatingseveral types of information contained in the received packet as the keyby providing the FQDN or the IP address uniquely indicating one or moretype of information related to the transfer method of that packet.

[0105] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using the FQDN or the IP address uniquely indicatingone or more type of information determined for each received packet asthe key by providing the FQDN or the IP address uniquely indicating oneor more information related to the transfer method of that packet.

[0106] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using the FQDN or the IP address uniquely indicatingone or more type of information contained in the received packet as thekey by providing the FQDN or the IP address uniquely indicating severaltypes of information related to the transfer method of that packet.

[0107] Thus, it becomes possible to reply to the inquiry from the packettransfer equipment using the FQDN or the IP address uniquely indicatingone or more type of information contained in the received packet as thekey by providing the FQDN or the IP address uniquely indicating one ormore type of information related to the transfer method of that packetthat is determined for each packet.

[0108] Other objects, features and advantages of the present inventionwill become clear from the detailed description given herebelow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0109] the present invention will be understood more fully from thedetailed description given herebelow and from the accompanying drawingsof the preferred embodiment of the invention, which, however, should notbe taken to be limitative to the invention, but are for explanation andunderstanding only.

[0110] in the drawings:

[0111]FIG. 1 is a block diagram showing the configuration of a firstembodiment according to the present invention;

[0112]FIG. 2 is a diagram showing an example of entries to the packettransfer method storage table according to the first embodiment of thepresent invention;

[0113]FIG. 3 is a diagram showing an example of entries to the packettransfer method database according to the first embodiment of thepresent invention;

[0114]FIG. 4 is a flowchart illustrating the operation of a packettransfer equipment according to the first embodiment of the presentinvention;

[0115]FIG. 5 is a flowchart illustrating the operation of a packettransfer method resolution server according to the first embodiment ofthe present invention;

[0116]FIG. 6 is a diagram showing an example of entries to the extractedpacket information correspondence table according to the firstembodiment of the present invention;

[0117]FIG. 7 is a diagram showing another example of entries to thepacket transfer method database according to the first embodiment of thepresent invention;

[0118]FIG. 8 is a diagram showing still another example of entries tothe packet transfer method database according to the first embodiment ofthe present invention;

[0119]FIG. 9 is a block diagram showing the configuration of a secondembodiment according to the present invention;

[0120]FIG. 10 is a diagram showing an example of entries to the IPaddress/FQDN correspondence database according to the second embodimentof the present invention;

[0121]FIG. 11 is a flowchart illustrating the operation of a packettransfer equipment according to the second embodiment of the presentinvention;

[0122]FIG. 12 is a diagram showing an example of messages sent betweenthe packet transfer equipment and a DNS server according to the secondembodiment of the present invention;

[0123]FIG. 13 is a block diagram showing the configuration of a thirdembodiment according to the present invention;

[0124]FIG. 14 is a diagram showing an example of conversions executed atthe extracted packet information conversion section according to thethird embodiment of the present invention;

[0125]FIG. 15 is a block diagram to show the configuration of a fourthembodiment according to the present invention;

[0126]FIG. 16 is a diagram showing an example of entry rewriting in thepacket transfer method database executed by an entry rewriting sectionaccording to the fourth embodiment of the present invention;

[0127]FIG. 17 is a block diagram showing the configuration of a fifthembodiment according to the present invention;

[0128]FIG. 18 is a diagram showing an example of entries to the packettransfer method database according to the fifth embodiment of thepresent invention;

[0129]FIG. 19 is a flowchart illustrating the operation of the packettransfer method resolution server according to the fifth embodiment ofthe present invention;

[0130]FIG. 20 is a block diagram showing the configuration of a sixthembodiment according to the present invention;

[0131]FIG. 21 is a diagram showing an example of the packet transferpolicies described in the packet transfer policy description sectionaccording to the sixth embodiment of the present invention;

[0132]FIG. 22 is a diagram showing an example of entries to the packettransfer method database according to the sixth embodiment of thepresent invention; and

[0133]FIG. 23 is a matrix showing the combinations between the types ofinformation contained in the packet and the types of information relatedto the transfer method.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0134] The preferred embodiment of the present invention will bediscussed hereinafter in detail with reference to the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be obvious, however, to those skilled in the art thatthe present invention may be practiced without these specific details.In other instance, well-known structures are not shown in detail inorder to unnecessary obscure the present invention.

[0135] (First Embodiment of the Invention)

[0136] Next, referring to the attached figures, a first embodiment ofthe present invention is described in details below.

[0137] Referring to FIG. 1, the first embodiment of the presentinvention is achieved by a packet transfer equipment A1 and a packettransfer method resolution server B1.

[0138] The packet transfer equipment A1 comprises a packet receiver A11,a packet storage A12, a packet information extraction section A13, apacket transfer method resolution section A14, a packet transfer methodstorage table A15, a packet processing section A16 and a packet senderA17.

[0139] The packet receiver A11 receives the packet sent by other nodeand once stores the received packet to the packet storage A12. Then, itsends the signal to indicate that it has received a packet to the packetinformation extraction section A13.

[0140] The packet storage A12 is a storage which, until the packetreceived by the packet receiver A11 is sent by the packet sender A17,temporarily stores the packet.

[0141] The packet information extraction section A13 is triggered byreceiving of the signal from the packet receiver A11 that indicatesreceiving of a packet and extracts the information contained in thepacket stored in the packet storage A12. In case of this embodiment, thepacket information extraction section A13 extracts one or more types ofpredetermined information in the received packet. Examples ofinformation extracted here include the URL, TCP/UDP port number,source/destination IP address, VLAN-ID and source/destination MACaddress. The information extracted here is not necessarily contained inone packet. The information obtained from the data generated throughsynthesis of two or more packets is also included. For example, the URLand the Cookie, which are application layer information, may be encodedover several packets on the TCP connection. In this case, it isnecessary to once terminate the applicable TCP connection at the packettransfer equipment A1 and to extract the URL and the Cookie. Inaddition, the extracted information is not necessarily of one type. Twotypes of information over several layers such as “URL and VLAN-ID” maybe extracted. In other words, one or more fixed type of information isextracted from the received packet and used as the key to resolve thetransfer method for that packet. The packet information extractionsection A13 passes the extracted information to the packet transfermethod resolution section A14.

[0142] The packet transfer method resolution section A14 resolves theproblem about how to process and transfer the received packet accordingto the information passed from the packet information extraction sectionA13. In this embodiment, there are two resolution methods: To searchentries stored in the packet transfer method storage table A15 or tomake an inquiry by sending the packet transfer method resolution requestto the packet transfer method resolution server B1. The packet transfermethod resolution request to the packet transfer method resolutionserver B1 may contain the information passed from the packet informationextraction section A13 as the key. The packet transfer method resolvedas described above is passed to the packet processing section A16.

[0143] The packet transfer method storage table A15 has entries showingthe correspondence between the information contained in the packet andthe transfer method for that packet registered. For example, a packettransfer method storage table 101 in FIG. 2 describes the packettransfer method when the types of information contained in the packetare “Destination port No., Destination IP Address and VLAN-ID”. Thefirst entry shows that the packet with the destination IP address10.1.1.1, the destination port No. 80 or 8080 and the vlan-ID 100 isrewritten so as to have the destination ID address 10.2.2.2 and thedestination MAC address 0x00:ab:da:32:45:67 and sent from an output port1. The second entry shows that the packet with the destination IPaddress 20.2.2.2, the destination port No. 7070 and the vlan-ID 200 isrewritten to have the destination port No. 8080 and the destination MACaddress 0x00:da:cf:12:34:56 and sent from an output port 2. In otherwords, this embodiment resolves the information related to the transfermethod of different types corresponding to the received packet. Thepacket transfer method storage table A15 is used to store the packettransfer method registered by setting to the packet transfer equipmentA1 itself or to temporarily cache the packet transfer method resolved byinquiry of the packet transfer method resolution server B1, but thepacket transfer equipment A1 may be configured without any packettransfer method storage table A15. In this case, the packet transfermethod resolution section A14 resolves the packet transfer method fromthe packet transfer method resolution server B1.

[0144] The packet processing section A16 processes the received packetstored in the packet storage A12 according to the packet transfer methodresolved by the packet transfer method resolution section A14. Forexample, in case of the packet corresponding to the second entry to thepacket transfer method storage table 101, the destination port No. ofthe received packet is rewritten from 7070 to 8080 and its destinationMAC address is rewritten to 0x00:da:cf:12:34:56. In addition, it alsoexecutes other processes not indicated directly in the packet transfermethod resolved by the packet transfer method resolution section A14(Rewriting of TTL (Time To Live) field, check sum field and so on in theIP header, for example) as required. After the packet processing, itsends the signal to request sending of the processed packet to thepacket sender A17.

[0145] When the packet sender A17 receives the signal to request packetsending from the packet processing section A16, it reads out theapplicable packet from the packet storage A12 and sends it to anothernode.

[0146] On the other hand, the packet transfer method resolution serverB1 comprises a packet transfer method resolution request acceptancesection B11 and a packet transfer method database B12.

[0147] The packet transfer method resolution request acceptance sectionB11 receives the resolution request for the packet transfer method fromthe packet transfer equipment A1, searches the packet transfer methoddatabase B12 for the packet transfer method to be replied to suchresolution request and makes a reply to the packet transfer equipmentA1.

[0148] The packet transfer method database B12 has entries showing thecorrespondence between the information contained in the packet and thetransfer method for that packet registered. For example, as in the caseshown by a packet transfer method database 102 in FIG. 3, it hasdescription about the packet transfer method when the types of theinformation contained in the packet are “Destination port No.,Destination IP address and vlan-ID”. In the first entry, the packethaving the destination IP address 20.1.1.1 and the destination port No.8080 and the vlan-ID 100 is rewritten to have the destination IP address20.2.2.2, the destination MAC address 0x00:12:34:56:78:9a and thevlan-ID 200 and then transferred. Further, the second entry shows atransfer method in which the packet having the destination IP address30.1.1.1 and the destination port No. 7070 and the vlan-ID 200 isrewritten to have the source IP address 40.1.1.1, the destination IPaddress 30.3.3.3, the destination port No. 80 and the destination MACaddress 0x00:bc:de:f0:12:34. This means rewriting of the fieldsdifferent from those rewritten in the first transfer method. In otherwords, the information related to different types of transfer methodscorresponding to the received packet is resolved. Further, the thirdentry indicates that, for the packet with the destination IP address40.1.1.1, an arbitrary destination port No. and the vlan-ID 100, thelabel 222 is added to the MPLS label field and the vlan-ID is deleted.Thus, the processing method for rewriting, addition and deletion inarbitrary fields of the received packet are described. In addition, byspecifying the rewriting or addition method for the destination IPaddress and the MPLS label of the received packet, the transfer route ofthe applicable packet is controlled.

[0149] Next, referring to FIG. 4, the operation from receiving tosending of the packet in the packet transfer equipment A1 in thisembodiment is described in details.

[0150] In the packet transfer equipment A1, when the packet receiver A11receives a packet from another node (Step S101 in FIG. 4), it stores thereceived packet to the packet storage A12 (Step S102).

[0151] After Step S102, the packet information extraction section A13 istriggered by receiving of the signal indicating packet receiving fromthe packet receiver A11, analyzes the received packet and extracts theinformation contained in the applicable packet (step S103).

[0152] When the information contained in the received packet isextracted at Step S103, the packet transfer method resolution sectionA14 resolves the transfer method of that packet. Firstly, the packettransfer method resolution section A14 searches the correspondence tablebetween the information contained in the received packet and thetransfer method of that packet in the packet transfer method storagetable A15 for the entry applicable to the received packet (Step S104).

[0153] If any applicable entry is found as a result of Step S104, thetransfer method of the received packet is resolved by the applicableentry (Step S105).

[0154] If any applicable entry is not found as a result of Step S104,the packet transfer method resolution request is sent to the packettransfer method resolution server B1 to inquire the transfer method ofthe received packet for resolution (Step S106). If the packet transfermethod resolution server B1 replies that there is no applicable entry,the received packet is judged to be abolished.

[0155] In case the transfer method of the received packet is resolved byinquiry of the packet transfer method resolution server B1 at Step S106,the entry is cached to the packet transfer method storage table A15 sothat there is no need of inquiry of the packet transfer methodresolution server B1 about the packet transfer method when the packethaving the same information is received next time (Step S107).

[0156] For the steps S106 and S107, the packet transfer equipment Alretains sending of the receive packet until the packet transfer methodis resolved by the packet transfer method resolution server B1. This mayincrease delay before sending. To cope with this concern, a defaultpacket transfer method may be set at the packet transfer method storagetable A15. The transfer method of the received packet is firstlyresolved by the default and sending is executed. Meanwhile, the packettransfer method resolution server B1 is inquired background and thetransfer method of the applicable packet is resolved and that transfermethod is cached to the packet transfer method storage table A15. Afterthus updating the entry, because the transfer method resolved by thepacket transfer method resolution server B1 is cached to the packettransfer method storage table A15, the transfer method can be alwaysresolved quickly. Here, the default transfer method is a transfer methodto make a resolution according to certain rules for any received packet.An example of the default transfer method may be the rule like this: thedestination IP address of the received packet is checked and the nextnode to which the applicable packet should be transferred is determinedbased on the IP routing table.

[0157] When the packet transfer method is resolved by Step S105 or Steps106 to S107, rewriting of the destination IP address and other processesare executed for the received packet stored in the packet storage A12according to the packet transfer method resolved by the packetprocessing section A16 (Step S108). The process to abolish theapplicable packet is included here.

[0158] Further, the packet processing section A16 judges whether to sendthe packet stored in the packet storage A12 that has been processed atStep S108 to another node or not (Step S109).

[0159] When it is judged to be sent at Step S109, the signal to requestpacket sending is sent to the packet sender A17 and the packet senderA17 sends the applicable packet to another node (Step S110).

[0160] When it is judged not to be sent at Step S109 (including the casewhere the packet is abolished at step S108), the processing isterminated as it is.

[0161] Next, referring to FIG. 5, the operation when the packet transfermethod resolution server B1 receives the packet transfer methodresolution request from the packet transfer equipment Al in thisembodiment is described in details.

[0162] When the packet transfer method resolution server B1 receives thepacket transfer method resolution request from the packet transferequipment A1, the packet transfer method resolution request acceptancesection B11 accepts the request (Step S201 in FIG. 5).

[0163] The packet transfer method resolution request acceptance sectionB11 recognizes the information contained in the packet for which thetransfer method is to be resolved from the received packet transfermethod resolution request and searches the packet transfer methoddatabase B12 for the entry applicable to that packet (Step S202).

[0164] If any entry applicable to the packet is found as a result ofStep S202, the transfer method for the packet indicated by that entry isreplied to the packet transfer equipment A1 (Steps S203, S204).

[0165] If any entry applicable to the packet is not found as a result ofStep S202, the message indicating that any applicable entry is not foundis replied to the packet transfer equipment A1 (Steps S203 and 205).

[0166] This embodiment as described above shows an example where one ormore fixed type of information is extracted from the receive packet asthe key to resolve the transfer method for the packet so that theinformation related to one or more type of transfer method determinedfor each received packet is resolved. This represents the conversion atB, D, J and L in the matrix of FIG. 23. However, the present inventionis applicable to the conversion at any one of B to P other than A shownin FIG. 23.

[0167] As in conversion at the positions E to H and M to P of FIG. 23,if one or more type of information determined for each received packetis extracted as the key to resolve the transfer method for that packet,the packet information extraction section A13 keeps the extracted packetinformation correspondence table describing the information about thetypes to be extracted corresponding to the received packet. The packetinformation extraction section A13 refers to this table to determine thetype of the information to be extracted from each received packet. FIG.6 shows an example of an extracted packet information correspondencetable. When such an extracted packet information correspondence table109 is used, the packet information extraction section A13 extracts theURL and the Cookie for the received packet having the destination portNo. 80 and extracts the destination address and the vlan-ID for thepacket having the destination port No. other than 80.

[0168] Further, if one or more type of information determined for eachreceived packet is used as the key, the information of the types thatcan be contained in the key is listed in the input packet informationcolumn of the packet transfer method database. For example, when severaltypes of information determined for each received packet are used as thekey to resolve the information related to several fixed types oftransfer methods regardless of the packet, a packet transfer methoddatabase 110 as shown in FIG. 7 is used. In addition, in case severaltypes of information determined for each received packet is used as thekey to resolve the information related to several types of transfermethods determined for each packet, a packet transfer method database111 as shown in FIG. 8 is used.

[0169] Next, the effect of this embodiment is described. According tothis embodiment, the packet transfer equipment A1 resolves all or anynecessary part of the information required for the transfer method ofthe received packet by making inquiries not only to the packet transfermethod storage table A15 in the same node, but also to the packettransfer method resolution server B1 outside. According to the priorart, even if the transfer method of the received packet is inquired ofan external server, such inquiry can resolve one type of limitedcorrespondence in a particular field of the packet only. To obtain allpieces or any necessary part of information required for the packettransfer method, the packet transfer equipment needs to have staticsetting by CLI or NMS inside. Setting by CLI and NMS has a drawback ofscalability: the control labor increases linearly for increase of thepacket transfer equipments to be controlled. According to thisembodiment, the packet transfer equipment A1 automatically resolves theset packet transfer method just with unique setting of the packettransfer methods to be controlled to the packet transfer methodresolution server B1. Specifically, the control labor is kept constanteven when the number of packet transfer equipments increases and thecentralized control of packet transfer methods can be realized with ahigh scalability.

[0170] (Second Embodiment of the Present Invention)

[0171] Next, referring to the attached drawings, a second embodiment ofthe present invention is described in details below.

[0172] This embodiment represents a case in which a DNS server is usedas the packet transfer method resolution server B1 in the firstembodiment of the present invention. The DNS server is usually used forresolution of the corresponding IP address from the FQDN or, on thecontrary, for resolution of the corresponding FQDN from the IP address.In this embodiment, the DNS server functions as a server to maparbitrary information contained in the packet to arbitrary type oftransfer method for that packet.

[0173] Referring to FIG. 9, the second embodiment of the presentinvention is achieved by a packet transfer equipment A2 and a DNS serverB2.

[0174] The configuration of the packet transfer equipment A2 isdifferent from that of the packet transfer equipment A1 according to thefirst embodiment of the present invention in that the former has apacket transfer method resolution section A21 instead of the packettransfer method resolution section A14.

[0175] The packet transfer method resolution section A21 resolves thetransfer method of the packet received by the packet transfer equipmentA2 for an external server by sending a DNS resolution request, which isa request to inquire of the DNS server B2 about the IP addresscorresponding to a certain FQDN or the FQDN corresponding to a certainIP address. Other functions are equivalent to those of the packettransfer method resolution section A14 in the packet transfer equipmentA1 according to the first embodiment of the present invention.

[0176] The DNS server B2 comprises a DNS resolution request acceptancesection B21 and an IP address/FQDN correspondence database B22.

[0177] The DNS resolution request acceptance section B21 receives theDNS resolution request from the packet transfer method resolutionsection A21 and replies to that request with referring to the IPaddress/FQDN correspondence database B22. It replies the correspondingIP address for a request to resolve the corresponding IP address fromthe FQDN (IP address resolution request) and replies the correspondingFQDN for a request to resolve the corresponding FQDN from the IP address(FQDN resolution request). It replies the message indicating that anyapplicable entry is not found if such corresponding IP address or FQDNis not found.

[0178] The IP address/FQDN correspondence database B22 is a database towhich the DNS resolution request acceptance section refers when it makesa reply to the IP address resolution request and the FQDN resolutionrequest it has received. This database comprises two databases: an IPaddress resolution database for correspondence from the FQDN to the IPaddress and an FQDN resolution database for correspondence from the IPaddress to the FQDN. FIG. 10 shows an example of the IP address/FQDNcorrespondence database B22. The IP address/FQDN correspondence databasecomprises an IP address resolution database 103 and an FQDN resolutiondatabase 104. An FQDN in the IP address resolution database 103 has thecontents to uniquely show several types of information contained in thereceived packet at the packet transfer equipment that transfers thereceived packet to another node. Another FQDN in the FQDN resolutiondatabase 104 corresponding to the same IP address as the onecorresponding to the above FQDN has the contents to uniquely show one ormore type of information related to the transfer method of the receivedpacket. Specifically, in case of this embodiment, the FQDN uniquelyshowing several types of information contained in the received packetand the FQDN uniquely indicating one or more type of information relatedto the transfer method of the received packet are indirectly associatedusing the IP address as the intermediate key.

[0179] Next, referring to FIGS. 10 and 11, the operation in which thepacket transfer method resolution section A21 of the packet transferequipment A2 makes an inquiry to the DNS server B2 to resolve thetransfer method of the packet received by the packet receiver A11 inthis embodiment is described in details below. Here, the IP address/FQDNcorrespondence database B22 of the DNS server B2 is assumed to have thecontents as shown in the IP address resolution database 103 and the FQDNresolution database 104, for example.

[0180] The packet transfer method resolution section A21 creates an FQDNfor inquiry as the IP address resolution request to the DNS server B2based on the information contained in the packet for which the transfermethod is to be resolved (Step S301 in FIG. 11). This FQDN creation isexecuted according to certain rules. For example, in case of a packethaving the destination TCP/UDP port number 7070, the destination IPaddress 20.1.1.1 and the vlan-ID 100, the FQDN is created asdstport-7070.dstip-20-1-1-1.vlan-100.resolve.org.

[0181] After Step S301, the IP address for the created FQDN is inquiredof the DNS server B2 in the form of the IP address resolution request(Step S302).

[0182] The DNS server B2 replies the corresponding IP address or, if anycorresponding IP address is not found, replies the message indicatingthat any applicable entry is not found (Step S303).

[0183] If the corresponding IP address can be resolved at Step S303, theFQDN for the resolved IP address is inquired of the DNS server B2 as theFQDN resolution request (Step S304). For example, if the resolved IPaddress is 192.168.1.1, this IP address is used as it is for the FQDNresolution request to the DNS server B2. This IP address is used as theintermediate key to resolve the FQDN at Step S306.

[0184] If the corresponding IP address cannot be resolved at Step S303,the packet received by the packet receiver A11 is decided to beabolished (Step S305).

[0185] When the FQDN resolution request is sent at Step S304, the DNSserver B2 replies the corresponding FQDN or, if any corresponding FQDNis not found, replies the message indicating that any applicable entryis not found (Step S306).

[0186] In case the corresponding FQDN is resolved at Step S306, theresolved FQDN is analyzed so that the packet transfer method isrecognized (Step S307). This recognition of the packet transfer methodis executed based on the resolved FQDN under certain rules. For example,if the resolved FQDN isdstip-20-2-2-2.dstmac00-12-34-56-78-0a.vlan-200.resolve.org, it isrecognized that the destination IP address is to be rewritten to20.2.2.2 and the destination MAC address to 0x00:12:34:56:78:0a and thevlan-ID to 200 for that packet. Further, if the resolved FQDN issrcip-30-3-33.dstport-8080.dstmac-00-bc-de-f0-12-34.resolve.org, it isrecognized that the source IP address is to be rewritten to 30.3.3.3 andthe destination port number to 8080 and the destination MAC address to0x00:bc:de:f0:12:34 for that packet.

[0187] If the corresponding FQDN cannot be resolved at Step S306, thepacket received by the packet receiver All is decided to be abolished(Step S305).

[0188]FIG. 12 shows an example of sequence for the steps S301 to S307above in which the packet transfer equipment A2 sends the IP addressresolution request for dstport-7070.dstip-20-1-1-1.vlan-100.resolve.orgto the DNS server B2 and the DNS server B2 finally replies the FQDNdstip-20-2-2-2.dstmac-00-12-34-56-78-0a.vlan200.resolve.org.

[0189] In the operation shown by Steps S301 to S307 and FIG. 12, thepacket transfer equipment A2 executes the IP address resolution requestonce and the FQDN resolution request once respectively to resolve thepacket transfer method. In addition to this, the packet transfer methodmay be resolved by sequence of the IP address resolution request and theFQDN resolution request respectively executed for arbitrary number oftimes corresponding to the operation.

[0190] An example is as follows. Firstly, the FQDN resolution request issent using the destination IP address of the received packet as the keyso as to resolve the corresponding FQDN. Then, the resolved FQDN iscombined with the information of the destination port number and thevlan-ID contained in the received packet to create a new FQDN and, usingsuch FQDN as the key, the IP address resolution request is sent so as toresolve the corresponding IP address. Further, the FQDN resolutionrequest is sent using the resolved IP address as the key so as toresolve the corresponding FQDN and, based on the resolved FQDN, thetransfer method of the received packet is resolved. In the sequence ofthis example, one IP address resolution request is combined with twoFQDN resolution requests.

[0191] In addition, though the FQDN uniquely indicating several types ofinformation contained in the received packet and the FQDN uniquelyindicating one or more type of information related to the transfermethod of the received packet are indirectly associated using the IPaddress as the intermediate key according to this embodiment, the IPaddress uniquely indicating several types of information contained inthe received packet and the IP address uniquely indicating one or moretype of information related to the transfer method of the receivedpacket may be indirectly associated using the FQDN as the intermediatekey. Further, the FQDN or the IP address uniquely indicating severaltypes of information contained in the received packet may be directlyassociated with the IP address or the FQDN uniquely indicating one ormore information related to the transfer method of the received packet.

[0192] Next, the effect of this embodiment is described. In thisembodiment, the DNS server B2 is used instead of the packet transfermethod resolution server B1 in the first embodiment of the presentinvention. Since the DNS server is generally used in the IP network asthe server for IP address resolution at present, it is not necessary toprepare a special server for resolution of the packet transfer method bythe packet transfer equipment. This facilitates the implementation ofthe present invention. In addition, the DNS has a hierarchical structureand, even if the DNS server receiving the IP address or FQDN inquiryitself does not have the corresponding entry, a DNS server of an upperlayer provides the information about the DNS server having thecorresponding entry so that the entry can be automatically resolved bythe DNS server having the corresponding entry. For this reason, it isnot necessary that the entry describing the packet transfer method forthe input packet information is controlled by a single DNS server. Itmay be controlled by several DNS servers distributed.

[0193] (Third Embodiment of the Invention)

[0194] Next, referring to the attached figures, a third embodiment ofthe present invention is described in details.

[0195] This embodiment represents a case in which the packet informationextraction section A13 automatically extracts the packet informationcorresponding to the type of the service to be rendered at the packettransfer equipment A1 in the first embodiment of the present invention.

[0196] Referring to FIG. 13, this embodiment can be achieved by a packettransfer equipment A3 and a packet transfer method resolution server B1.

[0197] The configuration of the packet transfer equipment A3 isdifferent from that of the packet transfer equipment A1 according to thefirst embodiment of the present invention in that the former has aservice input section A31 and an extracted packet information conversionsection A32.

[0198] At the service input section A31, the service to be rendered bythe packet transfer equipment A3 is set. For example, the equipment mayserve as a layer 2 switch, as a router or as a layer 7 switch. Inaddition to them, services to be rendered may be freely defined and set.

[0199] The extracted packet information conversion section A32 convertsthe service set at the service input section A31 to the packetinformation required to be extracted for provision of that service basedon the extracted packet information conversion table. An extractedpacket information conversion table 105 in FIG. 14 shows an example ofconversion from the service to the packet information. The convertedpacket information is set to the packet information extraction sectionA13 as the packet information to be extracted from the received packet.

[0200] This embodiment can be, as shown in the second embodiment of thepresent invention, achieved by the DNS server B2 used instead of thepacket transfer method resolution server B1.

[0201] Next, the effect of this embodiment is described. In thisembodiment, the packet information extracted by the packet informationextraction section A13 is not necessarily set one by one for each type.Just by setting the service to be rendered by the packet transferequipment A3, conversion from the set service to the extracted packetinformation is automatically executed. Therefore, this saves the laborof the setting manager of the packet transfer equipment A3.

[0202] (Fourth Embodiment of the Invention)

[0203] Next, referring to the attached figures, a fourth embodiment ofthe present invention is described in details.

[0204] This embodiment represents a case in which the packet transfermethod resolution server B1 according to the first embodiment of thepresent invention replies the packet transfer method inquired by thepacket transfer equipment A1 considering the resource situation of thenetwork used for transfer of that packet. For example, when the packettransfer equipment A1 receives a packet of the session that requires aband of 10 Mbps, the packet transfer method resolution server repliesthe packet transfer method so that such packet is transferred via theroute having a remaining band space of 10 Mbps.

[0205] Referring to FIG. 15, this embodiment is achieved by the packettransfer equipment A1 and the packet transfer method resolution serverB3. Among them, the packet transfer equipment A1 is the same as the onedescribed in the first embodiment of the present invention.

[0206] The packet transfer method resolution server B3 is different fromthe packet transfer method resolution server B1 described in the firstembodiment of the present invention in that it additionally has aresource information collection section B31 and an entry rewritingsection B32.

[0207] The resource information collection section B31 collects theresource information in the network via which the packet transferequipment A1 transfers the packet. Examples of resource informationinclude the maximum bandwidth between routers, the remaining bandwidthand the delay or the throughput information between edge nodes of thenetwork and the load on the server. Further, methods for resourceinformation collection include a method using SNMP (Simple NetworkManagement Protocol) and a method to measure the resource value bydirect sending of the measurement packet into the network by the packettransfer method resolution server B3.

[0208] The entry rewriting section B32 rewrites the entries in thepacket transfer method database B12 based on the resource information ofthe network collected by the resource information collection sectionB31. Two typical examples of the entry rewriting method based on theresource information are as follows: (i) When the packet transfer methodresolution request acceptance section B11 receives the packet transfermethod resolution request from the packet transfer equipment A1, thepacket transfer method database B12 requests rewriting of the applicableentry to the entry rewriting section B32; (ii) The entry rewritingsection B32 periodically checks the resource information and rewritesthe entry based on the resource information.

[0209] A packet transfer method database 106 in FIG. 16 shows an exampleof entries prepared as a result of rewriting of the entries in thepacket transfer method database B12 by the entry rewriting section B32.The URL contained in the HTTP request message is considered as the inputpacket information and, if it is “www.movie.org/aaa.fmt”, the transfermethod (In this case, the destination IP address, the destination MACaddress and the user-priority field of the MAC header are rewritten tospecified values and transferred) is determined so that the request isguided to the server with a larger downstream (Direction from server toclient) band. Further, if the URL is “www.text.net/bbb.txt”, thetransfer method is determined so that the request is guided to a serverwith a smaller delay before the server.

[0210] In another example, the LSP (Label Switched Path) of the MPLS(Multi-Protocol Label Switching) may be used for packet route control sothat the remaining band of each link in the applicable network is alwayskept to be 20% or more of the maximum physical band. In this case, thepacket transfer method resolution server B3 replies, to the packettransfer equipment A1, the MPLS label corresponding to the LSP throughwhich the packet is desired to pass as the packet transfer method. Thus,resource of that network is utilized at the maximum efficiency and themaximum number of users can be accommodated.

[0211] As shown in the second embodiment of the present invention, theDNS server B2 may be used as the packet transfer method resolutionserver. In this case, the resource information collection section B31and the entry rewriting section B32 are added to the configuration ofthe DNS server B2.

[0212] Next, the effect of this embodiment is described. In thisembodiment, when the packet transfer method resolution server B3 makes areply to the packet transfer method resolution request from the packettransfer equipment A1, it replies the packet transfer method consideringthe resource information of the network. With consideration of theresource information, the packet transfer can be controlled closelycorresponding to the characteristics of the packet.

[0213] (Fifth Embodiment of the Invention)

[0214] Next, referring to the attached figures, a fifth embodiment ofthe present invention is described in details.

[0215] This embodiment represents a case in which, when returning areply to the packet transfer method resolution request from the packettransfer equipment A1, the packet transfer method resolution server B1according to the first embodiment of the present invention makes arequest to control the resource on the nodes in the network together atthe same time (Reservation, priority control and so on) and controls thetransfer quality of the packet sent by the packet transfer equipment A1.

[0216] Referring to FIG. 17, this embodiment is achieved by the packettransfer equipment A1, a packet transfer method resolution server B4 anda network node C1. Among them, the packet transfer equipment A1 is thesame as the one described in the first embodiment of the presentinvention. The network node C1 is a node existing in the network viawhich the packet transfer equipment transfers the received packet. Itexecutes the transfer processing for the packets passing the network.Examples of the network node C1 include a router, a layer 2 switch andan ATM switch. There are usually several network nodes C1 in thenetwork, but the behavior of one such node is described here forsimplification.

[0217] The packet transfer method resolution server B4 is different fromthe packet transfer method resolution server B1 described in the firstembodiment of the present invention in that it additionally has aresource control request section B41.

[0218] The packet transfer method database B12 can contain theinformation related to the resource control as the transfer method forthe input packet. A packet transfer method database 107 in FIG. 18 showsan example of entries registered to the packet transfer method databaseB12. The first entry in the packet transfer method database 107 showsthat the band assurance of 10 Mbps is required at three passage nodes A,B and C as the resource control for the input packet. The second entryshows that, as the resource control for the input packet, the controlfor transfer with priority in the band up to 5 Mbps is required forthree passage nodes A, C and D. The third entry shows that any resourcecontrol is not required for the input packet.

[0219] If any resource control on the network node C1 in the network isrequired as the packet transfer method replied to the packet transferequipment A1 by the packet transfer method resolution request acceptancesection B11, the resource control request section B41 makes a request tocontrol the resource on the network node C1 by sending the resourcecontrol request to the network node C1. In case of the packet transfermethod database 107, the resource control request to assure a band of 10Mbps for the applicable packet is sent to the network nodes A, B and Cfor the first entry. For the second entry, the resource control requestfor transfer with priority up to 5 Mbps for the applicable packet issent to the network nodes A, C and D.

[0220] The network node C1 contains a resource control requestacceptance section C11 and a resource control section C12.

[0221] The resource control request acceptance section C11 receives theresource control request from the packet transfer method resolutionserver B4 and sets the resource control section C12 so that therequested resource control can be executed. Then, it replies whether therequested resource control is successfully set or not to the packettransfer method resolution server B4.

[0222] The resource control section C12 actually controls the resourcein relation to the network node C1 (link band or the like).

[0223] Next, referring to FIG. 19, the operation in which the packettransfer method resolution server B4 receives the packet transfer methodresolution request from the packet transfer equipment A1 and returns areply to the packet transfer equipment A1 in this embodiment isdescribed in details.

[0224] When the packet transfer method resolution request from thepacket transfer equipment A1 is received by the packet transfer methodresolution server B4, the packet transfer method resolution requestacceptance section B11 accepts that request (Step S401 in FIG. 19).

[0225] The packet transfer method resolution request acceptance sectionB11 recognizes, from the received packet transfer method resolutionrequest, the information contained in the packet for which the transfermethod is to be resolved. It searches the packet transfer methoddatabase B12 for the entry applicable to that packet (Steps S402 andS403).

[0226] If any entry applicable to that packet is not found as a resultof Step S403, the message indicating that no applicable entry is foundis replied to the packet transfer equipment A1 (Step S405).

[0227] If any entry applicable to that packet is found as a result ofStep S403, the packet transfer method resolution request acceptancesection B11 judges whether the packet transfer method described in suchentry requires the resource control or not (Step S404).

[0228] If the resource control is found necessary as a result of StepS404, the required resource control is identified and the resourcecontrol request is sent to the network node C1 via the resource controlrequest section B41 (Step S406).

[0229] If the resource control is found unnecessary as a result of StepS404, the packet transfer method read at Step S403 is replied to thepacket transfer equipment A1.

[0230] When the resource control request sent at Step S406 is accepted,the packet transfer method read at Step S403 is replied to the packettransfer equipment A1 (Steps S407 and S408).

[0231] When the resource control request sent at Step S406 is notaccepted, the processing goes back to Step S402 and makes retrial (StepsS407 and S409). However, if the trial has been already executed for thelimited number set in advance, the trial is not made and the messageindicating that the applicable entry is not found is replied to thepacket transfer equipment A1 (Steps S409 and S405).

[0232] Though the packet transfer method resolution server B4 sends theresource control request to the network node C1 in this embodiment, theresource control request may be also sent to the network node C1 by thepacket transfer equipment A1 based on the information contained in thetransfer method resolved with the packet transfer method resolutionserver B4. In this case, the packet transfer equipment A1 has thefunction corresponding to the resource control request section B41.

[0233] In addition, as shown in the second embodiment of the presentinvention, this embodiment may be realized using the DNS server B2 asthe packet transfer method resolution server. In this case, the resourcecontrol request section B41 is added to the configuration of the DNSserver B2. For example, the DNS resolution request acceptance sectionB11 recognizes whether the resource control is required or not asfollows: If the FQDN indicating the packet transfer method replied tothe packet transfer equipment A1 is “rsvbw-10 Mbps.node-A-B-C.dstip-20-2-2-2.dstmac-00-12-34-56-78-0a.vlan200.resolve.org”, the section“rsvbw-10 Mbps.node-A-B-C” is read and it is recognized that the bandreservation for 10 Mbps is required at nodes A, B and C.

[0234] Next, the effect of this embodiment is described. In thisembodiment, when the packet transfer method resolution server B4 sends areply to the packet transfer method resolution request from the packettransfer equipment A1, it makes a request for the resource control onthe node in the network at the same time so as to control the transferquality of the packet sent by the packet transfer equipment A1. Bycontrolling the network resource at the same time, close packet transfercontrol corresponding to the characteristics of the packet can beachieved as in the fourth embodiment of the present invention.

[0235] (Sixth Embodiment of the Invention)

[0236] Next, referring to the attached figures, a sixth embodiment ofthe present invention is described in details.

[0237] This embodiment represents a case in which the packet transfermethod resolution server B1 according to the first embodiment of thepresent invention controls the packet transfer method to be repliedbased on the packet transfer policy input from outside when replying thepacket transfer method inquired by the packet transfer equipment A1 sothat the business to obtain consideration for such control from thenetwork users is realized. The network users here represent the endusers at home and office and the service providers who provide servicessuch as various contents and applications to the end users.

[0238] Referring to FIG. 20, this embodiment is realized by the packettransfer equipment A1 and a packet transfer method resolution server B5.Among them, the packet transfer equipment A1 is the same as the onedescribed in the first embodiment of the present invention.

[0239] The packet transfer method resolution server B5 is different fromthe packet transfer method resolution server B1 described in the firstembodiment of the present invention in that it has a packet transferpolicy description section B51 and an entry rewriting section B52 inaddition to the configuration of the packet transfer method resolutionserver B1.

[0240] The packet transfer policy description section B51 describes thepolicy to control the packet transfer method replied to the packettransfer method resolution request from the packet transfer equipmentA1. An example of the packet transfer policy is shown in a packettransfer policy description table 108 of FIG. 21. In this example, thefirst entry describes the policy to provide the priority for 1000 timesat most to the processing as follows: to rewrite the request packethaving the URL “www.portal.com” and the destination port number “80” sothat it has the URL “www.biglobe.net” and the destination IP address“20.1.1.1” and to transfer such packet. The second entry describes thepolicy according to which 60% of the request packet having the URL“www.abc.org” and the destination port number “8080” is rewritten sothat it has the URL “www.xyz.com”, the destination IP address “30.1.1.1”and the vlan-ED “100” and is transferred.

[0241] The entry rewriting section B52 rewrites the entries in thepacket transfer method database B12 based on the packet transfer policydescribed in the packet transfer policy description section B51. FIG. 22shows an example of the packet transfer method database rewritten by theentry rewriting section B52 when the packet transfer policy descriptiontable 108 of FIG. 21 is used as the packet transfer policy. Referring toa packet transfer method database 112 of FIG. 22, the first entrydescribes two transfer methods: a method to rewrite the request packethaving the URL “www.portal.com” and the destination port number “80” tohave the URL “www.biglobe.net”, the destination address “20.1.1.1” andthe vlan-ID “100” and transfer such packet; and a method to rewrite onlythe vlan-ID to “100” and transfer such packet. Selection standard columnshows the selection standard that the former method is selected withpriority for 1,000 more times (this number of times is to be reducedcorresponding to the times of selection) and the latter is selected indefault setting (selected when there is no other transfer method to beselected with priority). In addition, the second entry describes twotransfer methods: a method to rewrite the request packet having the URL“www.abc.org” and the destination port number “8080” so that it has theURL “www.xyz.com” and the destination IP address “30.1.1.1” and totransfer such packet; and a method to rewrite the vlan-ID to “100” andto transfer such packet. The selection standard column shows theselection standard to select the former method with a weight of 60% andthe latter method with a weight of 40%.

[0242] Next, examples of business models according to this embodimentare described below.

[0243] According to a first business model, the contents serviceprovider or the application service provider has the packet transfermethod resolution server B5 execute the control to guide the contentsacquisition request or application execution request from the user toits own server and pays the consideration to the network serviceprovider managing the packet transfer method resolution server B5.Conventionally, there have been services in which the search serverdisplays the link to the URL of the provider of that service at a highrank in the list displayed as the search result so as to guide therequest from the user positively. However, there has been no service toguide the request from the user through control by the network.

[0244] According to a second business model, the packet transfer methodresolution server B5 controls the transfer method of the request fromthe user corresponding to the user's context information (such as theuser location, device used by the user, current time and user's taste).For example, in response to a request for map display, the transfer iscontrolled so that the request is guided to the server that displays themap of the user's location based on the user's location information(Source IP address, vlan-ID and so on). Alternatively, in response to arequest for access to a web site of nearby restaurants, the transfer iscontrolled so that the request is guided to the web site of therestaurants that are currently open. In this business model, the usersor the contents service providers or the application service providerspay the consideration to the network service provider managing thepacket transfer method resolution server B5.

[0245] This embodiment may be, as shown in the second embodiment of thepresent invention, realized using the DNS server B2 as the packettransfer method resolution server. In this case, the packet transferpolicy description section B51 and the entry rewriting section B52 areadded to the configuration of the DNS server B2.

[0246] Next, the effect of this embodiment is described. This embodimentis to run the business in which the packet transfer method replied tothe packet transfer equipment A1 is controlled according to the packettransfer policy input from outside and consideration for such control ispaid by the network users. With this embodiment, a new business asdescribed in the business model example above can be realized.

[0247] Though the present invention has been described with listingseveral embodiments so far, the present invention is not limited to theabove embodiments and can be enhanced or modified in various ways. Inaddition, the functions of the packet transfer equipment, the packettransfer method resolution server and the DNS server of the presentinvention can be realized of course by the hardware and also can berealized by the computer and programs. The packet transfer equipmentprogram, the packet transfer method resolution server program and theDNS server program are recorded and provided in the computer-readablerecording media such as magnetic disks or semiconductor memories so thatthey are read by the computer when the computer is booted up, forexample, and they control the operation of the computer to have thatcomputer function as the packet transfer equipment, the packet transfermethod resolution server and the DNS server in the above embodiments.

[0248] A first effect is that the management of the packet transferequipment can be centralized. Because the present invention enables thepacket transfer equipment to automatically resolve the correspondencerepresented at B to P in FIG. 23 by inquiring of the packet transfermethod resolution server outside about the transfer method of thereceived packet, it is not necessary to set the packet transfer methodin each packet transfer equipment.

[0249] A second effect is that the management of the packet transferequipment can be centralized using an existing DNS server. This isbecause the present invention enables the existing DNS server to serveas the packet transfer method resolution server.

[0250] A third effect is that a new business style can be realized. Thisis because the present invention enables setting of the policy for thepacket transfer control profitable for a particular network user to thepacket transfer method resolution server and can thereby have the packettransfer equipment execute the packet transfer based on such packettransfer policy. Thus, a business model to obtain consideration fromnetwork users can be realized.

[0251] Although the invention has been illustrated and described withrespect to exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omissions and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodies within a scope encompassed andequivalents thereof with respect to the feature set out in the appendedclaims.

In the claims:
 1. A packet transfer equipment that transfers thereceived packet to another node characterized by that the packettransfer equipment specifies several types of information contained insaid received packet, inquires of an external server about one or moretype of information related to the transfer method of said receivedpacket and resolves the transfer method of said received packetaccording to one or more type of information obtained.
 2. A packettransfer equipment that transfers the received packet to another nodecharacterized by that the packet transfer equipment specifies one ormore type of information in said received packet that is determined foreach of said received packet, inquires of an external server about oneor more type of information related to the transfer method of saidreceived packet and resolves the transfer method of said received packetaccording to one or more type of information obtained.
 3. A packettransfer equipment that transfers the received packet to another nodecharacterized by that the packet transfer equipment specifies one ormore type of information in said received packet, inquires of anexternal server about several types of information related to thetransfer method of said received packet and resolves the transfer methodof said received packet according to several types of informationobtained.
 4. A packet transfer equipment that transfers the receivedpacket to another node characterized by that the packet transferequipment specifies one or more type of information contained in saidreceived packet, inquires of an external server about one or more typeof information related to the transfer method of said received packetthat is determined for each of said received packet and resolves thetransfer method of said received packet according to one or more type ofinformation obtained.
 5. A packet transfer equipment as set forth inclaim 1 wherein: the information resolved by said external server as theinformation related to the packet transfer method contains at least oneof the information related to rewriting of the information contained inthe received packet, the information related to the information added tothe received packet, the information related to the information deletedfrom the received packet, the information related to the control methodof the route through which the received packet is transferred and theinformation related to the resource control method for the route throughwhich the received packet is transferred.
 6. A packet transfer equipmentthat transfers the received packet to another node comprising: a packetinformation extraction section that extracts several types ofinformation contained in said received packet, and a packet transfermethod resolution section that specifies said several types ofinformation extracted by said packet information extraction section andinquires of an external server about one or more type of informationrelated to the transfer method of said received packet and resolves thetransfer method of said received packet according to one or more type ofinformation obtained.
 7. A packet transfer equipment that transfers thereceived packet to another node comprising: a packet informationextraction section that extracts one or more type of informationcontained in said received packet that is determined for each of saidreceived packet, and a packet transfer method resolution section thatspecifies said one or more type of information extracted by said packetinformation extraction section, inquires of an external server about oneor more type of information related to the transfer method of saidreceived packet and resolves the transfer method of said received packetaccording to one or more type of information obtained.
 8. A packettransfer equipment that transfers the received packet to another nodecomprising: a packet information extraction section that extracts one ormore type of information contained in said received packet, and a packettransfer method resolution section that specifies said one or more typeof information extracted by said packet information extraction section,inquires of an external server about several types of informationrelated to the transfer method of said received packet and resolves thetransfer method of said received packet according to several types ofinformation obtained.
 9. A packet transfer equipment that transfers thereceived packet to another node comprising: a packet informationextraction section that extracts one or more type of informationcontained in said received packet and a packet transfer methodresolution section that specifies said one or more type of informationextracted by said packet information extraction section, inquires of anexternal server about one or more type of information related to thetransfer method of said received packet that is determined for each ofsaid received packet and resolves the transfer method of said receivedpacket according to one or more information obtained.
 10. A packettransfer equipment as set forth in claim 6 wherein: the informationresolved by said external server as the information related to thepacket transfer method contains at least one of the information relatedto rewriting of the information contained in the received packet, theinformation related to the information added to the received packet, theinformation related to the information deleted from the received packet,the information related to the control method of the route through whichthe received packet is transferred and the information related to theresource control method for the route through which the received packetis transferred.
 11. A packet transfer equipment as set forth in claim 6wherein: said packet information extraction section extracts theinformation encoded over two or more packets.
 12. A packet transferequipment as set forth in claim 6 further comprising a packet transfermethod storage table that temporarily stores the information related tothe packet transfer method resolved by said packet transfer methodresolution section and characterized by that said packet transfer methodresolution section checks whether said packet transfer method storagetable stores any information related to the transfer method of saidreceived packet before inquiring of an external server about informationrelated to the transfer method of said received packet and, if saidpacket transfer method storage table stores the information related tothe transfer method of said received packet, reads out the informationrelated to the transfer method of said received packet from said packettransfer method storage table and thereby resolves the transfer methodof said received packet.
 13. A packet transfer equipment as set forth inclaim 6 wherein: said packet transfer method resolution section uses theinformation contained in said received packet extracted by said packetinformation extraction section to create the FQDN and/or the IP addressuniquely indicating the information contained in said received packet.14. A packet transfer equipment as set forth in claim 6 wherein: saidpacket transfer method resolution section uniquely recognizes thetransfer method of said received packet based on the FQDN or the IPaddress resolved with the domain name system server.
 15. A packettransfer equipment as set forth in claim 6 wherein: said packet transfermethod resolution section resolves the FQDN or the IP address uniquelyindicating the packet transfer method corresponding to the informationcontained in said received packet extracted by said packet informationextraction section by repeating the request for resolution of the FQDNor the IP address one or more times to the domain name system server.16. A packet transfer equipment as set forth in claim 6 wherein saidpacket transfer method resolution section uses the information containedin said received packet extracted by said packet information extractionsection to create the FQDN uniquely indicating the information containedin said received packet, inquires of the domain name system server,using said FQDN as the key, about the IP address corresponding to saidFQDN, inquires of said domain name system server, using the IP addresscorresponding to said FQDN replied by said domain name system server asthe key, about the FQDN corresponding to said IP address and uniquelyrecognizes the transfer method of said received packet based on the FQDNcorresponding to said IP address replied from said domain name systemserver.
 17. A packet transfer equipment as set forth in claim 6 furthercomprising: a service input section to set the type of the service to berendered and an extracted packet information conversion section to makeconversion to the type of information contained in said received packetextracted by said packet information extraction section corresponding tosaid type of service set to said service input section.
 18. A packettransfer equipment as set forth in claim 6 further comprising: aresource control request section that, if the resource control for othernodes in the network is required as additional information of the packettransfer method resolved by said packet transfer method resolutionsection, makes a request for resource control of said other nodes.
 19. Apacket transfer method resolution server characterized by that, upon arequest from the packet transfer equipment that transfers the receivedpacket to another node inquiring the information related to the transfermethod of said received packet and specifying several types ofinformation contained in said received packet, one or more type ofinformation related to the transfer method of said received packet isreplied to said packet transfer equipment.
 20. A packet transfer methodresolution server characterized by that, upon a request from the packettransfer equipment that transfers the received packet to another nodeinquiring the information related to the transfer method of saidreceived packet and specifying one or more type of information containedin said received packet that is determined for each of said receivedpacket, one or more type of information related to the transfer methodof said received packet is replied to said packet transfer equipment.21. A packet transfer method resolution server characterized by that,upon a request from the packet transfer equipment that transfers thereceived packet to another node inquiring the information related to thetransfer method of said received packet and specifying one or more typeof information contained in said received packet, several types ofinformation related to the transfer method of said received packet arereplied to said packet transfer equipment.
 22. A packet transfer methodresolution server characterized by that, upon a request from the packettransfer equipment that transfers the received packet to another nodeinquiring the information related to the transfer method of saidreceived packet and specifying one or more type of information containedin said received packet, one or more type of information related to thetransfer method of said received packet that is determined for each ofsaid received packet is replied to said packet transfer equipment.
 23. Apacket transfer method resolution server as set forth in claim 19wherein: the information replied to said packet transfer equipment asthe information related to the packet transfer method contains at leastone of the information related to rewriting of the information containedin the received packet, the information related to the information addedto the received packet, the information related to the informationdeleted from the received packet, the information related to the controlmethod of the route through which the received packet is transferred andthe information related to the resource control method for the routethrough which the received packet is transferred.
 24. A packet transfermethod resolution server comprising: a packet transfer method databasewhere the correspondences between several types of information containedin the packet and one or more type of information related to the packettransfer method are registered, and a packet transfer method resolutionrequest acceptance section that accepts the packet transfer methodresolution request from the packet transfer equipment that transfers thereceived packet to another node inquiring the information related to thetransfer method of said received packet and specifying several types ofinformation contained in said received packet, refers to said packettransfer method database and replies one or more type of informationrelated to the transfer method of said received packet to said packettransfer equipment.
 25. A packet transfer method resolution servercomprising: a packet transfer method database where the correspondencesbetween one or more type of information contained in the packet and oneor more type of information related to the packet transfer method areregistered, and a packet transfer method resolution request acceptancesection that accepts the packet transfer method resolution request fromthe packet transfer equipment that transfers the received packet toanother node inquiring the information related to the transfer method ofsaid received packet and specifying one or more type of informationcontained in said received packet that is determined for each of saidreceived packet, refers to said packet transfer method database andreplies, to said packet transfer equipment, one or more type ofinformation related to the transfer method of said received packet. 26.A packet transfer method resolution server comprising: a packet transfermethod database where the correspondences between one or more type ofinformation contained in the packet and several types of informationrelated to the packet transfer method are registered, and a packettransfer method resolution request acceptance section that accepts thepacket transfer method resolution request from the packet transferequipment that transfers the received packet to another node inquiringthe information related to the transfer method of said received packetand specifying one or more type of information contained in saidreceived packet, refers to said packet transfer method database andreplies, to said packet transfer equipment, several types of informationrelated to the transfer method of said received packet.
 27. A packettransfer method resolution server comprising: a packet transfer methoddatabase where the correspondences between one or more type ofinformation contained in the packet and one or more type of informationrelated to the packet transfer method are registered, and a packettransfer method resolution request acceptance section that accepts thepacket transfer method resolution request from the packet transferequipment that transfers the received packet to another node inquiringthe information related to the transfer method of said received packetand specifying one or more type of information contained in saidreceived packet, refers to said packet transfer method database andreplies, to said packet transfer equipment, one or more type ofinformation related to the transfer method of said received packet thatis determined for each of said received packet.
 28. A packet transfermethod resolution server as set forth in claim 24 wherein: theinformation replied to said packet transfer equipment as the informationrelated to the packet transfer method contains at least one of theinformation related to rewriting of the information contained in thereceived packet, the information related to the information added to thereceived packet, the information related to the information deleted fromthe received packet, the information related to the control method ofthe route through which the received packet is transferred and theinformation related to the resource control method for the route throughwhich the received packet is transferred.
 29. A packet transfer methodresolution server as set forth in claim 24 further comprising: aresource information collection section that collects the resourceinformation in the network and an entry rewriting section that rewritesentries registered to said packet transfer method database based on theresource information in said network collected by said resourceinformation collection section.
 30. A packet transfer method resolutionserver as set forth in claim 24 further comprising: a resource controlrequest section that, if the resource control for other nodes in thenetwork is necessary, sends a request for resource control of said othernodes as the additional information of said transfer method when saidpacket transfer method resolution request acceptance section replies theinformation related to said transfer method in response to said packettransfer method resolution request from said packet transfer equipment.31. A packet transfer method resolution server as set forth in claim 24further comprising: a packet transfer policy description section thatdescribes the policy to control the information related to said transfermethod replied by said packet transfer method resolution requestacceptance section in response to said packet transfer method resolutionrequest from said packet transfer equipment, and an entry rewritingsection that rewrites entries registered to said packet transfer methoddatabase based on said policy described in said packet transfer policydescription section.
 32. A DNS server comprising: an IP address/FQDNcorrespondence database having the IP address corresponding to the FQDNand the FQDN corresponding to the IP address registered where the FQDNor the IP address in the packet transfer equipment that transfers thereceived packet to another node uniquely indicating several types ofinformation contained in said received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of said received packet are associated, and a DNSresolution request acceptance section that accepts the IP addressresolution request inquiring the IP address corresponding to the FQDNfrom the packet transfer equipment that transfers the received packet toanother node, refers to said IP address/FQDN correspondence database andreplies the IP address corresponding to said FQDN to said packettransfer equipment as well as accepts the FQDN resolution requestinquiring the FQDN corresponding to the IP address from said packettransfer equipment, refers to said IP address/FQDN correspondencedatabase and replies the FQDN corresponding to said IP address to saidpacket transfer equipment.
 33. A DNS server comprising: an IPaddress/FQDN correspondence database having the IP address correspondingto the FQDN and the FQDN corresponding to the IP address registeredwhere the FQDN or the IP address in the packet transfer equipment thattransfers the received packet to another node uniquely indicating one ormore type of information in said received packet determined for each ofsaid received packet and the FQDN or the IP address uniquely indicatingone or more type of information related to the transfer method of saidreceived packet are associated, and a DNS resolution request acceptancesection that accepts the IP address resolution request inquiring the IPaddress corresponding to the FQDN from the packet transfer equipmentthat transfers the received packet to another node, refers to said IPaddress/FQDN correspondence database and replies the IP addresscorresponding to said FQDN to said packet transfer equipment as well asaccepts the FQDN resolution request inquiring the FQDN corresponding tothe IP address from said packet transfer equipment, refers to said IPaddress/FQDN correspondence database and replies the FQDN correspondingto said IP address to said packet transfer equipment.
 34. A DNS servercomprising: an IP address/FQDN correspondence database having the IPaddress corresponding to the FQDN and the FQDN corresponding to the IPaddress registered where the FQDN or the IP address in the packettransfer equipment that transfers the received packet to another nodeuniquely indicating one or more type of information in said receivedpacket and the FQDN or the IP address uniquely indicating several typesof information related to the transfer method of said received packetare associated, and a DNS resolution request acceptance section thataccepts the IP address resolution request inquiring the IP addresscorresponding to the FQDN from the packet transfer equipment thattransfers the received packet to another node, refers to said IPaddress/FQDN correspondence database and replies the IP addresscorresponding to said FQDN to said packet transfer equipment as well asaccepts the FQDN resolution request inquiring the FQDN corresponding tothe IP address from said packet transfer equipment, refers to said IPaddress/FQDN correspondence database and replies the FQDN correspondingto said IP address to said packet transfer equipment.
 35. A DNS servercomprising: an IP address/FQDN correspondence database having the IPaddress corresponding to the FQDN and the FQDN corresponding to the IPaddress registered where the FQDN or the IP address in the packettransfer equipment that transfers the received packet to another nodeuniquely indicating one or more type of information in said receivedpacket and the FQDN or the IP address uniquely indicating one or moretype of information determined for each of said received packet relatedto the transfer method of said received packet are associated, and a DNSresolution request acceptance section that accepts the IP addressresolution request inquiring the IP address corresponding to the FQDNfrom the packet transfer equipment that transfers the received packet toanother node, refers to said IP address/FQDN correspondence database andreplies the IP address corresponding to said FQDN to said packettransfer equipment as well as accepts the FQDN resolution requestinquiring the FQDN corresponding to the IP address from said packettransfer equipment, refers to said IP address/FQDN correspondencedatabase and replies the FQDN corresponding to said IP address to saidpacket transfer equipment.
 36. A DNS server as set forth in claim 32wherein: the FQDN or the IP address replied by said DNS resolutionrequest acceptance section to said packet transfer equipment uniquelyindicates the information related to one or more arbitrary transfermethod contained in the processing method of rewriting, addition anddeletion for one or more arbitrary piece of information in said receivedpacket and/or the route through which said received packet istransferred and the resource control method for said route.
 37. A DNSserver as set forth in claim 32 further comprising: a resourceinformation collection section that collects the resource information inthe network and an entry rewriting section that rewrites entriesregistered to said IP address/FQDN correspondence database based on theresource information in said network collected by said resourceinformation collection section.
 38. A DNS server as set forth in claim32 further comprising: a resource control request section that, if theresource control for other nodes in the network is judged necessary,sends a request for resource control to said other nodes when said DNSresolution request acceptance section replies the IP addresscorresponding to said FQDN and the FQDN corresponding to said IP addressin response to said IP address resolution request and said FQDNresolution request from said packet transfer equipment.
 39. A DNS serveras set forth in claim 32 further comprising: a packet transfer policydescription section that describes the policy to control the IP addresscorresponding to said FQDN and the FQDN corresponding to said IP addressreplied by said DNS resolution request acceptance section in response tosaid IP address resolution request and said FQDN resolution request fromsaid packet transfer equipment, and an entry rewriting section thatrewrites entries registered to said IP address/FQDN correspondencedatabase based on said policy described in said packet transfer policydescription section.
 40. A network system comprising a packet transferequipment and a packet transfer method resolution server or a DNSserver, and characterized by that the policy to guide the request packetfrom the user requesting contents or application services to the serverof a particular provider is described in said packet transfer methodresolution server or said DNS server.
 41. A network system comprising apacket transfer equipment and a packet transfer method resolution serveror a DNS server, and characterized by that the policy to execute thetransfer control of the request packet from the user requesting saidcontents or application services provided by the contents or applicationservice provider based on the context information of said user isdescribed in said packet transfer method resolution server or said DNSserver.
 42. A program to have a computer function as a packet transferequipment that transfers the received packet to another node comprising:a packet information extraction function to extract several types ofinformation contained in said received packet, and a packet transfermethod resolution function that inquires of an external server about oneor more type of information related to the transfer method of saidreceived packet with specifying said several types of extractedinformation and resolves the transfer method of said received packetaccording to one or more type of information obtained.
 43. A program tohave a computer function as a packet transfer equipment that transfersthe received packet to another node comprising: a packet informationextraction function to extract one or more type of information in saidreceived packet determined for each of said received packet and a packettransfer method resolution function that inquires of an external serverabout one or more type of information related to the transfer method ofsaid received packet with specifying said one or more type of extractedinformation and resolves the transfer method of said received packetaccording to one or more type of information obtained.
 44. A program tohave a computer function as a packet transfer equipment that transfersthe received packet to another node comprising: a packet informationextraction function to extract one or more type of information containedin said received packet, and a packet transfer method resolutionfunction that inquires of an external server about several types ofinformation related to the transfer method of said received packet withspecifying said one or more type of extracted information and resolvesthe transfer method of said received packet according to several typesof information obtained.
 45. A program to have a computer function as apacket transfer equipment that transfers the received packet to anothernode comprising a packet information extraction function to extract oneor more type of information contained in said received packet, and apacket transfer method resolution function that inquires of an externalserver about one or more type of information related to the transfermethod of said received packet that is determined for each of saidreceived packet with specifying said one or more type of extractedinformation and resolves the transfer method of said received packetaccording to one or more type of information obtained.
 46. A program tohave a computer function as a packet transfer method resolution serverprovided with a packet transfer method database where thecorrespondences between several types of information contained in thepacket and one or more type of information related to the packettransfer method are registered comprising: a packet transfer methodresolution request acceptance function that accepts the packet transfermethod resolution request from the packet transfer equipment thattransfers the received packet to another node inquiring the informationrelated to the transfer method of said received packet and specifyingseveral types of information contained in said received packet, refersto said packet transfer method database and replies to said packettransfer equipment one or more type of information related to thetransfer method of said received packet.
 47. A program to have acomputer function as a packet transfer method resolution server providedwith a packet transfer method database where the correspondences betweenone or more type of information contained in the packet and one or moretype of information related to the packet transfer method are registeredcomprising: a packet transfer method resolution request acceptancefunction that accepts the packet transfer method resolution request fromthe packet transfer equipment that transfers the received packet toanother node inquiring the information related to the transfer method ofsaid received packet and specifying one or more type of information insaid received packet determined for each of said received packet, refersto said packet transfer method database and replies to said packettransfer equipment one or more type of information related to thetransfer method of said received packet.
 48. A program to have acomputer function as a packet transfer method resolution server providedwith a packet transfer method database where the correspondences betweenone or more type of information contained in the packet and severaltypes of information related to the packet transfer method areregistered comprising: a packet transfer method resolution requestacceptance function that accepts the packet transfer method resolutionrequest from the packet transfer equipment that transfers the receivedpacket to another node inquiring the information related to the transfermethod of said received packet and specifying one or more type ofinformation contained in said received packet, refers to said packettransfer method database and replies several types of informationrelated to the transfer method of said received packet to said packettransfer equipment.
 49. A program to have a computer function as apacket transfer method resolution server provided with a packet transfermethod database where the correspondences between one or more type ofinformation contained in the packet and one or more type of informationrelated to the packet transfer method are registered comprising: apacket transfer method resolution request acceptance function thataccepts the packet transfer method resolution request from the packettransfer equipment that transfers the received packet to another nodeinquiring the information related to the transfer method of saidreceived packet and specifying one or more type of information in saidreceived packet, refers to said packet transfer method database andreplies to said packet transfer equipment one or more type ofinformation related to the transfer method of said received packet thatis determined for each of said received packet.
 50. A program to have acomputer function as a DNS server provided with an IP address/FQDNcorrespondence database where the IP address corresponding to the FQDNand the FQDN corresponding to the IP address are registered and the FQDNor the IP address in the packet transfer equipment that transfers thereceived packet to another node uniquely indicating several types ofinformation contained in said received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of said received packet are associated comprising: afunction that accepts the IP address resolution request inquiring the IPaddress corresponding to the FQDN from the packet transfer equipmentthat transfers the received packet to another node, refers to said IPaddress/FQDN correspondence database and replies the IP addresscorresponding to said FQDN to said packet transfer equipment, and afunction that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from said packet transfer equipment,refers to said IP address/FQDN correspondence database and replies theFQDN corresponding to said IP address to said packet transfer equipment.51. A program to have a computer function as a DNS server provided withan IP address/FQDN correspondence database where the IP addresscorresponding to the FQDN and the FQDN corresponding to the IP addressare registered and the FQDN or the IP address in the packet transferequipment that transfers the received packet to another node uniquelyindicating one or more type of information in said received packetdetermined for each of said received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of said received packet are associated comprising: afunction that accepts the IP address resolution request inquiring the IPaddress corresponding to the FQDN from the packet transfer equipmentthat transfers the received packet to another node, refers to said IPaddress/FQDN correspondence database and replies the IP addresscorresponding to said FQDN to said packet transfer equipment, and afunction that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from said packet transfer equipment,refers to said IP address/FQDN correspondence database and replies theFQDN corresponding to said IP address to said packet transfer equipment.52. A program to have a computer function as a DNS server provided withan IP address/FQDN correspondence database where the IP addresscorresponding to the FQDN and the FQDN corresponding to the IP addressare registered and the FQDN or the IP address in the packet transferequipment that transfers the received packet to another node uniquelyindicating one or more type of information contained in said receivedpacket and the FQDN or the IP address uniquely indicating several typesof information related to the transfer method of said received packetare associated comprising: a function that accepts the IP addressresolution request inquiring the IP address corresponding to the FQDNfrom the packet transfer equipment that transfers the received packet toanother node, refers to said IP address/FQDN correspondence database andreplies the IP address corresponding to said FQDN to said packettransfer equipment, and a function that accepts the FQDN resolutionrequest inquiring the FQDN corresponding to the IP address from saidpacket transfer equipment, refers to said IP address/FQDN correspondencedatabase and replies the FQDN corresponding to said IP address to saidpacket transfer equipment.
 53. A program to have a computer function asa DNS server provided with an IP address/FQDN correspondence databasewhere the IP address corresponding to the FQDN and the FQDNcorresponding to the IP address are registered and the FQDN or the IPaddress in the packet transfer equipment that transfers the receivedpacket to another node uniquely indicating one or more type ofinformation contained in said received packet and the FQDN or the IPaddress uniquely indicating one or more type of information related tothe transfer method of said received packet that is determined for eachof said received packet are associated comprising: a function thataccepts the IP address resolution request inquiring the IP addresscorresponding to the FQDN from the packet transfer equipment thattransfers the received packet to another node, refers to said IPaddress/FQDN correspondence database and replies the IP addresscorresponding to said FQDN to said packet transfer equipment, and afunction that accepts the FQDN resolution request inquiring the FQDNcorresponding to the IP address from said packet transfer equipment,refers to said IP address/FQDN correspondence database and replies theFQDN corresponding to said IP address to said packet transfer equipment.